Problem Description

Online Media Asset Handling (*.youtube and *.vimeo files) in the TYPO3 backend is vulnerable to denial of service. Putting large files with according file extensions results in high consumption of system resources. This can lead to exceeding limits of the current PHP process which results in a dysfunctional backend component. A valid backend user account or write access on the server system (e.g. SFTP) is needed in order to exploit this vulnerability.

Solution

Update to TYPO3 versions 7.6.32, 8.7.21 or 9.5.2 that fix the problem described.

Credits

Thanks to Michael Schams who reported this issue and to TYPO3 core team member Oliver Hader who fixed the issue.